P127
In the purity of unhindered awareness, in turning away from concern
with the conditioned, the wholly peaceful and clear reality is revealed.

P137
In listening to dzogchen teachings it is clear that the aim of the practice is
to establish the mind in ‘innate, self-arising rigpa’; this latter word – for which the
Skt. is vidyæ and the Pali vijjæ (transcendent knowing) – is variously translated as
‘non-dual awareness,’ ‘innate wisdom,’ ‘pure presence,’ ‘primordial being.’ Again
and again its principal qualities are ennumerated: empty of essence, cognizant in
nature, unconfined in capacity. Or, using a different translation of these terms:
emptiness, knowing, and lucidity or clarity. Again, the translations into English
vary but, on consideration, the resemblance to the adjectives describing the mind
“where long and short etc. can find no footing” is striking.

P191
The reason why we have grouped these three qualities – knowing,
emptiness and the radiant mind – together for this chapter was first touched on in
Chapter 8. The environment of pure awareness is cultivated through a realization
of emptiness and then embodies that characteristic as a result of its perfection.
Radiance is another of the principal qualities that manifests as that knowing is
purified.

P192
Buddha-wisdom is the ultimate subject; Dhamma is the ultimate object;
the field of their interplay is supremely bright; all these elements are empty of self.
Enlightenment, liberation, depends on the recognition of the radical separateness
of awareness – ‘the one who knows’ as Ajahn Chah would phrase it – and the
world of the five khandhas. Having said that, it’s also crucial to note that the
phrase ‘the one who knows’ (‘poo roo’ in Thai) is a colloquialism that has differ-
ent meanings in different contexts. It can be used (at one end of the spectrum) for
‘that which cognizes an object,’ to (at the other end) ‘supramundane wisdom.’
Most often it is used in simple concentration instructions, where the meditator
separates awareness from the object and then focuses on the awareness. The
separate awareness of full awakening is of a different order altogether.

There's plenty more mention of "awareness", which you can search for in the PDF, but that's probably enough for a start...

Other passages mention a consciousness in this freedom — "without feature or surface, without end, luminous all around" — lying outside of time and space, experienced when the six sense spheres stop functioning (MN 49). In this it differs from the consciousness-khandha, which depends on the six sense spheres and can be described in such terms as near or far, past, present, or future. Consciousness without feature is thus the awareness of Awakening. And the freedom of this awareness carries over even when the awakened person returns to ordinary consciousness. As the Buddha said of himself:

14. Maturity Knowledge
Immediately afterwards, a type of knowledge manifests itself that, as it were, falls for the first time into Nibbāna, which is void of formations (conditioned phenomena) since it is the cessation of them. This knowledge is called “maturity knowledge.”

15. Path Knowledge
It is followed immediately by knowledge that abides in that same Nibbāna, which is void of formations since it is the cessation of them. This is called “path knowledge.” It is also called “purification by knowledge and vision.”

P137
In listening to dzogchen teachings it is clear that the aim of the practice is
to establish the mind in ‘innate, self-arising rigpa’; this latter word – for which the
Skt. is vidyæ and the Pali vijjæ (transcendent knowing) – is variously translated as
‘non-dual awareness,’ ‘innate wisdom,’ ‘pure presence,’ ‘primordial being.’ Again
and again its principal qualities are ennumerated: empty of essence, cognizant in
nature, unconfined in capacity. Or, using a different translation of these terms:
emptiness, knowing, and lucidity or clarity. Again, the translations into English
vary but, on consideration, the resemblance to the adjectives describing the mind
“where long and short etc. can find no footing” is striking.

This is kind of what I mean by descriptives that make it at least easier to approach and probably help in some respect to development.

Are there other descriptions and or words that are used by other teachers in the Theravada tradition in regards to nibbana like this?

Hi Chris.
Only a person who attain Nibbana will be able to tell what Nibbana is and understand it too.
What is important for me is to hear what is your understanding about Nibbana.
Considering that Nibbana as the final destination, you may have some understanding about your journey.
If we can discuss that, it will be more helpful to you and I.
Having said that I will stay within the Sutta description of Nibbana until I realise myself what Nibbana meanas.

I have no idea what nibbana is lol. And I think the Buddha was right when he never talked directly about it because it defies words (Unconditioned).

But I think there is something to be said about writing things like the above masters have. It helps I think in developing the right path to Nibbana. It also helps in developing the mind in skillful ways I think.

Hi Chris
I agree, please read as much as you can and most importantly practice at least a little.
Just start with five precepts and Brhama Viharas.
Do not accept anything that any one tells (even Suttas) until you realise it your own!
Obviously you have to have some faith on Buddha.

Venerable Silananda talks briefly on Nibbana, which I find to be useful.

(pg. 35)

Nibbana is the Highest of the ultimate realities. Until we see Nibbana for ourselves, until we realize Nibbana for ourselves, it is not yet an ultimate reality for us. I may say "May I attain Nibbana" or "May you attain Nibbana" or "I do this meritorious deed so I may get to Nibbana." We always say that. When we say, "Nibbana", the Nibbana we are taking in our mind is not the real Nibbana. It is just the name-concept, Nibbana. But when we see it for ourselves, when we experience the enlightenment for ourselves, then we will know Nibbana through direct experience. Only then will Nibbana become ultimate reality for us. Until we reach that stage, although Nibbana is an ultimate reality, it is not yet an ultimate reality for us.

Nibbana is defined as the extinction of desire, ill-will and delusion. Actually it is the extinction of all mental defilements. It is like health or peace.......What is health? No disease. Freedom from disease or having no disease is called health. So health is a positive state, but it is described as absence of disease, absence of illness. Peace is also like that. Nibbana is the extinction of desire, ill-will and delusion. Actually that means Nibbana is the extinction of all mental defilements. Also it is described as liberation or freedom from suffering. We can say it is the extinction of all suffering.

later on he mentions health like Nibbana again and says something along the lines of "you cannot see health, we can experience health, when we say we are healthy we are talking about the characteristics of what healthy is," somewhat combining the two statements above together.

Then, http://www.accesstoinsight.org/tipitaka ... .than.html
Now, to the extent that there is theme-less awareness-release, the unprovoked awareness-release is declared the foremost. And this unprovoked awareness-release is empty of passion, empty of aversion, empty of delusion.

It does seems strage to say nibbana is awareness, rather something more like there can be nibbanic awareness. So to me it does not seem enough to simply talk about awareness since it is qualifed above. A key word here being unprovoked (panakuppa), as a qualifier to awareness....something about a mind steady and unshakeable. The idea being a nibbana mind/awareness is not driven about by craving I suppose. Also generally speaking there is a sense of nibbana as something that is constant and stays like awareness and not like the mental objects which come and go.